This is the name of a NASA space program that resulted in the launch in 1970 of a spacecraft, sending two bullfrogs into orbit for the study of the effect of weightlessness.
The name “Otolith” refers to the part of the inner ear that is associated with the equilibrium control. The purpose of the mission was to investigate the effect of microgravity on the otolith. Bullfrogs have been chosen because they have an inner ear labyrinth that is very similar to the ones of human.
Initially planned in 1966 (what a great year ;-) ) the OFO was orbited on the 9th of November 1970. It staid in orbit for seven days, no recover was planned (which means that the fate of the two poor frogs was fixed since the beginning…)
As almost all space programs this event has been commemorated via postal covers. Here is one.
The left side of the cover pictures the details of the OFO spacecraft.
The cover is cancelled on the day of the launch with a mechanical cancel from Wallops Island, Virginia. Wallops Island is a small island located off the east coast of Virginia. It hosts Wallops Flight Facility operated by NASA since 1945 to launch all sort of rockets, including the one that orbited the OFO.
The cover is franked with a nice stamp issued by USA on the 9th of July 1970 to commemorate the 150th anniversary of the statehood of state of Main. Main became a state on the 15th of March 1820. The stamp pictures a painting from my one of my favorite painters, Edward Hopper. The painting is called “Lighthouse at two lights” and is currently displayed in the Metropolitan Museum of Art in New York.